San Agustin de Callo Project, Ecuador

San Agustin de Callo Project, Ecuador

By Dr. David O. Brown

Hacienda CourtyardStanding at the foot of Cotopaxi volcano, just northeast of the village of Lasso in central Ecuador, the small hacienda of San Agustín de Callo preserves many aspects of its Spanish colonial heritage (Figure 1). The red tile roof, white-plastered stone walls, and the charming cobblestone courtyard grace a site whose ancestry includes having served as a small monastery for the Augustinian friars from Quito, just two hours to the north of the hacienda along the Pan-American highway. Tourists from around the world visit the lovely San Agustín hacienda and the spectacular snow-capped Cotopaxi volcano, judged by many as one of Ecuador's most beautiful scenic wonders. A few lucky tourists spend the night at the hacienda in recently refurbished rooms with freshly painted murals and period furniture.

Inka Door A closer look at the hacienda reveals vestiges of the fine stonework that characterizes the construction style of the Inkas, whose pre-Hispanic empire stretched from central Chile to southern Colombia in the century before the Spanish conquest (Figure 2). The hacienda building at San Agustín de Callo, one of Ecuador's oldest, was not just built atop an Inka site, but actually incorporated Inka buildings into its construction. The Inkas, whose imperial capital lay a thousand miles to the south at Cusco, Peru, conquered most of modern Ecuador at the end of the fifteenth century, founding numerous settlements along the way. A few of these sites still stand away from modern settlements, such as Ingapirca in southern Ecuador, where one finds some of the most beautiful Inka stonework outside of Cusco. Other sites, such as the major Inka center at Tomebamba whose ruins lie within the southern Ecuadorian city of Cuenca, are buried or barely visible under modern towns and cities. The Inka site at San Agustín marks the farthest northern extent of the fine stonework that characterizes the most prestigious structures of the Inka culture.

Alexander von Humboldt's Wall Elevation at Callo There is considerable speculation about San Agustín's Inka origins. Was it, as some have suggested, a palace of Huayna Capac, one of the last Inka rulers, or was it a sanctuary devoted to the spirits of Cotopaxi? Or was it merely a way station on the Inka road from Cuenca to Quito? Whatever the site's original purpose, its Inka ancestry has long been recognized. The French geodesic expedition of the early eighteenth century stayed at the hacienda, publishing the first known drawing of the site. Less than a century later, the great German geographer, Alexander von Humboldt, visited the site, leaving us a brief description with several excellent drawings (Figure 3).

Students Mapping CalloDespite having been known for so many years, the site has only recently been investigated by archaeologists. Dr. David O. Brown, a Research Fellow at the Texas Archeological Research Laboratory, has been studying the site for four years. His initial investigations at the site were conducted with faculty members and students at the Universidad San Francisco de Quito, where Dr. Brown taught in 1995 (Figure 4). The team of archaeologists, architects, and historians from USFQ have carefully documented many aspects of the hacienda's Inka and Spanish Colonial heritage. Preliminary excavations revealed previously unknown Inka and Spanish Colonial features as well as artifacts that span the range of the site's history (Figure 5).

Colonial CoinThanks to a grant from the National Geographic Society, Dr. Brown and his team returned to San Agustín in December of 1998 to begin new excavations aimed at better understanding the site's long and colorful history. Among the 1998-1999 goals were the search for the remains of other Inka buildings which may have fallen into ruin in the centuries since the site's original construction, such as the fragmentary wall of an Inka building that now stands to one side of the hacienda courtyard (Figure 6). Additionally the team was looking for clues to the original function of the site, as well as evidence of the various phases of its colonial past, including roles as a private estate of the early conquistadors, a rural outpost of the Augustinian friars, and a textile factory where local villagers made cloth for European markets.

Ruined Wall in Courtyard This team included TARL Research Fellow Dana Anthony, who served as assistant project director, as well as scholars from Ecuador, including archaeologists Byron Camino and Oscar Manosalvas of the Museo Jijón y Caamaño at the Pontífica Universidad Católica del Ecuador and vulcanologists Minard Hall and Patricia Mothes of the Instituto Geofísico at the Escuela Politécnica Nacional of Quito. Hall and Mothes, who have spent years studying the ancient volcanic sediments of the region, are among the researchers monitoring the current activity of the nearby Pichincha and Tungurahua volcanoes (follow the eruptions daily in Spanish at


Controlled Surface Collections.

The 1998-99 excavations at San Agustín considerably expanded our knowledge of the site. Excavations and surface collection (Figure 7) away from the main hacienda compound revealed that both Spanish Colonial and Inka materials are widespread and that the site may have had greater extent in the past. Several important cultural features, including the Inka road, Inka stone terraces, and apparent Inka canals, as well as the remains of a Spanish Colonial mill (Figure 8) were identified north of the main hacienda complex.

Spanish Colonial Mill Arch

Volcanic Stratigraphy in Unit Profile

The excavations outside the compound also provided a clear picture of the natural volcanic stratigraphy of the site. Strata of ash and pumice airfalls are interlayered with volcanic debris and mud flows with very little soil development and little evidence of human occupation of the small hilltop until the arrival of the Inka (Figure 9). Comparison of these volcanic strata with widespread dated events from Cotopaxi and the nearby Quilotoa volcano show that the upper two meters of excavated stratigraphy at San Agustín dates back several thousand years (Figure 10).

Cotopaxi Volcano Seen over Hacianda

Brown, Hall & Mothes Examining a Wall Lying along the edge of one of the main channels of debris flow coming off of the volcano, there is evidence that the site has suffered from volcanic and seismic activities over the last 500 years. In support of historic documents that mention such local disasters, there are colonial era volcanic mud and debris flows that have partially buried walls at the site (Figure 11). Likewise, severe cracks and displacements along the Inka wall are probably the result of frequent earthquakes in this tectonically active zone.



Inka Foundation Overlying Volcanic Layers

The recent excavations have uncovered evidence of Inka construction techniques at the site. The Inka apparently leveled the hillside first, seeking one of the more indurated volcanic layers to provide a stable, level base for their construction. Many of the Inka walls have their basal layer just on top of a very hard mud flow which is roughly dated between 800 and 2200 years BP. On this base, they built three courses of foundation, which were subsequently buried by introduced fill (Figure 12). While these three subterranean courses have many of the characteristics of fine Inka stonework, they are not nearly so well made as the upper layers. Curiously, these hidden courses feature some of the smallest blocks used by the Inka at the site. In contrast, overlying these smaller stones, the first visible course is massive, providing a visual impression of stability.

Inka Stonework Detail The Inka walls were dry-lain, with the blocks above the foundation courses set so precisely that a knife cannot be inserted between the blocks (Figure 13). Except where blocks have shifted from seismic activity over the centuries, these joints are as tight as ever. While the exterior faces of the blocks fit together nicely, the blocks themselves are wedge-shaped, and the interior faces do not meet. Instead, the core of the wall is filled with a very fine volcanic ash that was used to provide a solid base for the wall stones. For this dry mortar, the Inkas sought out a unique sediment, ash from an eruption of the Quilotoa volcano dated around 800 BP. This ash was present in a very thin layer across the site prior to the Inka construction. A few remnants of this layer were discovered in the excavations; across most of the site this ash is missing, probably removed during the Inka construction.

Northern Excavation Unit (Callo Hill Behind) Excavations at the site recovered large quantities of ceramics, bone and other remains (Figure 14). One of the more interesting discoveries was the very low density of Inka ceramics. Most of the materials can be dated to the colonial era when occupation of the site was the most intense. Ceramics found in the Inka construction fill layers represent mostly local styles, probably the remains of the people who were brought here to build the site. The few Inka sherds that have been identified are mostly utilitarian types, not the more familiar Cusco Polychrome styles that one might expect to be associated with the extremely fine stonework at the site, some of the finest in all of Ecuador. The discovery of an unfinished Inka block (Figure 15) in one of the excavations suggests a possible reason for the paucity of Inka ceramics - the site may have still been under construction at the time of the Spanish conquest.

Unfinished Inka Block in Unit 17

Colonial Wall Foundation in Unit 19 Colonial era cultural remains predominate at the site. Many of the foundation walls are colonial as are some of the canals and drains and the water mill arch. Though massive, the colonial foundations are easily distinguished from their Inka counterparts by the unshaped stones, rough faces, and the use of mortar to fill in gaps in the colonial walls (Figure 16). The continued use of the site since its initial construction around the beginning of the sixteenth century makes for a complex juxtaposition of Inka, colonial and modern elements such as seen in the photo of the Inka foundation behind a buried historic stone-lined canal and a modern water pipe (Figure 17).

Inka Wall and Historic Canal The San Agustín de Callo project has been funded for a second season by the National Geographic Society. Beginning in mid-January, the team will continue investigations at the site. Many of the features discovered during the 1998-1999 season will be investigated in greater detail in the upcoming investigations. In addition, the 2000 season will feature use of ground penetrating radar in the search for other hidden cultural features such as walls and canals. Look for periodic updates as the season progresses.

For more information on the site and the ongoing investigations, contact Dr. Brown by writing to TARL, or to Dr. Brown at and for information about visiting the site in Ecuador, see the hacienda's web site at http:/




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